Chemistry Reference
In-Depth Information
0.1
10
11
0.01
10
10
10
9
20
40
60
80 100
TEMPERATURE (ºC)
120
140
160
180
200
(a)
10
10
10
9
10
8
20
40
60
80 100
TEMPERATURE (ºC)
120
140
160
180
200
(b)
FIGURE 4.20
(a) Storage modulus and tan
of an oriented poly(ethylene terephthalate) fiber. 11-Hz
frequency. (b) Loss modulus of the same fiber.
δ
EXAMPLE 4-4
An interesting application of dynamic mechanical data is in blends of rubbers for tire treads.
Rolling is at low frequencies, while skidding is at high frequencies. (Compare the hum of
tires on the pavement with the screech of a skid.) Therefore, low rolling friction requires low
damping (i.e., little dissipation of mechanical energy) at low frequencies while skid resis-
tance implies high damping at higher frequencies. One way to achieve the desired property
balance is to blend elastomers with the respective properties.
